The use of auto-exp-NK cells in this protocol makes therapy available to all refractory high risk MM patients, 2/3 of whom would otherwise not have a suitable haploidentical donor. We have shown that NK cells can be expanded both from newly diagnosed high risk MM patients and from refractory, previously heavily treated patients, the very individuals in need of novel therapies such as exp-NK cell infusions. Furthermore, we observed that exp-NK cells have the ability to kill auto-MM cells in vitro compared to no killing with resting auto-NK cells. This may be due to the elevated activation state of exp-NK cells, which allows them to overcome otherwise dominant inhibitory signaling. The incorporation of the proteasome inhibitor bortezomib, which down regulates the principal NK cell inhibitory ligands on MM cells should further increase the efficacy of auto-exp-NK cells. Because there is no risk for GvHD, CD3+ T cell depletion will not be necessary for auto-exp-NK cell products.